As an imaging device that is used in a vehicle-mounted camera or a monitoring camera there is a known imaging device that comprises a lens holder that holds a lens, a substrate for mounting an imaging element, and a base member for securing the lens holder and the substrate (income for example, Japanese Unexamined Patent Application Publication 2005-215369). In the imaging device disclosed in Patent Japanese Unexamined Patent Application Publication 2005-215369, the center of the imaging element is aligned to the axis of a cylindrical portion of the base member, and is secured to the base member. Moreover, the lens holder is secured to the base member through screwing a male threaded portion of the lens holder into a female threaded portion of the cylindrical portion of the base member after adjusting the focus of the imaging device.